The present disclosure is related to marking and printing systems, and more particularly to a shaped fuser reflector to reflect back to heat a fuser assembly that accommodates variable print media.
In a typical xerographic image forming device, a toner image is formed on a medium such as print media, and then the toner is heated to fuse the toner on the medium. One process for thermally fusing toner onto media uses a fuser assembly including a pressure roll, a fuser roll typically hollow to accommodate a heating source, a fusing nip between the rolls, and a heating lamp in the center of the fuser roll. The heating lamp radiates heat onto the outer surface of the fuser roll or a belt. The fuser is contained within a thermally isolating housing that can reflect some of the radiated heat back to the fuser roll. The heated fuser roll or belt is pressed against the pressure roll or belt forming the fusing nip. The heating lamp extends the full width of the printing process in order to suitably heat and fuse toner to the widest print media used with the image forming device. The fusing heat is typically controlled by measuring the temperature of the fuser roll or belt and feeding the temperature information to a controlled power supply in the image forming device.
The temperature across the fuser roller has to be consistent to provide an accurate fusing. As the lamp heats the fuser roll, and the heat is transferred to the print media which cools the fuser, the temperature becomes uneven. If smaller print media sizes are fused the whole fuser is heated wasting energy. Additionally, excessive heating of components forming the fuser assembly can be very damaging. In order to prevent thermal damage, steps are taken to limit the overheating of the portion of the fuser assembly that does not contact narrower print media such as paper media sheets. Typically, the inter-page gap between successive media sheets being printed is increased when media sheets less than the full width are used. However, increasing the inter-page gap between successive media sheets slows the printing process down which may increase a customer frustration with the imaging forming device. Accordingly, an improved fuser assembly for use with printing on narrower media sheets is desired.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for concentrating fuser heat on the parts of the fuser roll needed to be heated and for lowering power consumption in a fuser assembly.